Social control of spermatogenesis and steroidogenesis in cichlid fish: a comparative approach

MARÍA FLORENCIA SCAIA; LUCIANO CAVALLINO; MATIAS PANDOLFI

REPRODUCTION

BIOSCIENTIFICA LTD

Lugar: Bristol; Año: 2020

1470-1626

Social animals with hierarchical dominance systems are susceptible to changes their environment. Interactions with conspecifics cangreatly affect individual?s behavior and reproductive success. This review will show how social behavior modulates gonadalsteroidogenesis and spermatogenesis in African and Neotropical cichlid fish with different social systems and how this modulationregulates reproductive capacity. Social behavior and aggressiveness are strongly linked to sex steroids, glucocorticoids andneuropeptides. The challenge hypothesis suggests that behavioral interactions increase androgen levels in response to socialinstability, but there is little evidence regarding estradiol levels. It has been recently demonstrated that in male Cichlasoma dimerus, aNeotropical cichlid fish, the challenge hypothesis could also be extended to estrogens. In C. dimerus, dominant males have highergonadosomatic index than subordinated; the percentage of spermatocytes and spermatids is higher in subordinates, while dominantsshow a greater percentage of spermatozoa. In other species of African cichlids, socially suppressed subordinate males are notreproductively incompetent maintaining some activity at every level of their reproductive axis. Axis reactivation upon social ascent issimilar to the initiation of puberty in mammals, as well as the reoccurrence of puberty observed in seasonally breeding animals. Inconclusion, social behavior and reproductive strategies in females cichlids are still understudied, and Neotropical cichlids stillconstitute a group that deserves more attention, considering cichlids? diversity in mating systems, reproductive behavior and parentalcare. This review highlights the importance of performing further studies and additional research in these two areas, which stillremain to be addressed.